Once upon a time, a perception arose that the lightweight barrel was inferior to a heavier barrel. Wether this is true or not is a whole 'nuther topic which will only be a pissing match between those who like HBARs and those who don't.
Also, as stated earlier, it is cheaper for the manufacturers to produce HBAR barrels.
You see so many HBARs on the EE because people are finding the HBAR isn't necessary for what they want/use their AR for.
Now, if you can get a screamin' deal on an HBAR, you could get it turned down under the handguards for a psuedo goverment profile-but obviously the deal has to be good enough to justify the extra expense.
Personally, I can find a use/purpose for all profiles available-that is why I have more than one AR. If I were to pick one type only, it would probably be goverment profile.